When US President Barack Obama offered his rationale for supporting the UN imposed no-fly zone over Libyan skies, he said that "We knew that if we waited one more day, Benghazi - a city nearly the size of Charlotte - could suffer a massacre that would have reverberated across the region and stained the conscience of the world."

To those who would, in coming days, criticise him for having stood idly by in the wake of repression elsewhere, he said: "It is true that America cannot use our military wherever repression occurs. And given the costs and risks of intervention, we must always measure our interests against the need for action. But that cannot be an argument for never acting on behalf of what's right. In this particular country - Libya, at this particular moment, we were faced with the prospect of violence on a horrific scale."

Pundits and analysts have tried to gauge a doctrine from this speech - under what circumstances will the president send soldiers into harm's way? How does one balance the nature of America's interest against the costs and risks of intervention? One thing is sure - one cannot expect America to launch military strikes everywhere and all the time.

Do not expect, then, a similar mission over Syria. But if there should be a balance between interest and conscience, what to make of Syria?

Syria's dictator Bashar al-Assad has had already more than 400 peaceful protesters murdered and the body count is growing, daily. Loyalist brigades have now surrounded city of Dara'a, the epicentre of anti-government protests, and have been shelling the town for days. There are reports of Iranian Revolutionary Guards participating in the repression. Isn't this a situation where "the costs and risks of intervention" should not be "an argument for never acting on behalf of what's right"?

It is remarkable that Muammar Gaddafi gets what no other regional tyrant who is a sworn enemy of the West is getting. Consider this: Gaddafi gave up his military nuclear programme in 2004 - Assad did not; Gaddafi gave up support for international terrorism - Assad is still a main sponsor of terrorism; Gaddafi supported counter radicalisation programmes for former Al-Qaeda jihadis - Assad facilitated their transit into Iraq; Gaddafi improved relations with the West - Assad improved relations with Iran; Gaddafi turned over at least one perpetrator of the Lockerbie bombing to justice - Assad shielded the murderers of the late Lebanese Prime minister, Rafiq Hariri, from justice.

Finally, turning Libya to rebel control has, at least so far, no discernible strategic benefit - Gaddafi was already our friend, sold us his oil and had willingly stopped all activities that constituted a strategic threat to the West since 2004. Turning Syria, by contrast, would constitute far-reaching benefits. Its patronage of Hizbollah and Hamas would in all likelihood come to an end; and so would its alliance with Iran.

Why then, cannot the US and Europe begin by recalling envoys, suspending the EU Association Agreement with Syria, expanding asset freezes to the entire Assad family, initiating proceedings to bring Assad to The Hague, and stating: "Assad must go"?